I did this last year on Halloween for running errands during the day...really simple...
I used black eyeliner to draw out the "new" line of my eyebrows (also to fill them in a little) and the portion of my lips/mouth that are black. The black eyeshadow filled in the remaining bits around my eyes for a soft look.
The other part of my lips was filled in with white eyeliner (I think, might have been something else) with the white eyeshadow used to set the liner and give the rest of my face a more "doll" look.
Then just grab some black and white clothing and *POOF!* - all done!

You could do this with any number of colour combinations...go crazy.